Shell is aiming to sell $30bn of assets by 2018 as it seeks to pay off debt following its takeover of BG Group.

The deal represents about half of Shell's 2016 North Sea output.

Chrysaor will become the largest independent operator in the North Sea after the deal's completion.

On completion of the North Sea deal, about 400 staff will transfer to Chrysaor, "subject to a detailed scoping exercise and staff consultation", Shell said.

"This transaction shows the clear momentum behind Shell's... divestment programme," the company said.

Shell's interests in Buzzard, Beryl, Bressay, Elgin-Franklin, J-Block, the Greater Armada cluster, Everest, Lomond and Erskine - plus a 10% stake in Schiehallion - will be sold as part of the deal.

The firm said it expected to "record an accounting gain" on the sale, which includes Shell and former BG assets.

Shell's chief financial officer Simon Henry said the deal "builds on recent upstream divestments in the Gulf of Mexico and Canada."

He added that the firm wanted to "simplify our portfolio following the acquisition of BG".

In April 2015, Shell agreed to buy the oil and gas exploration firm in a deal that valued the business at £47bn. The final deal value was £36.4bn.

Shell cut thousands of jobs after the BG deal, and announced more than 10,000 job cuts globally.

Also on Tuesday, Shell said it would sell its stake in Thailand's Bongkot gas field to the Kuwait Foreign Petroleum Exploration Company for $900m.